The present disclosure relates to a display apparatus, and more particularly, to a display apparatus that can improve the brightness uniformity by making brightness of pixels connected to a last gate line be equal to that of pixels other than the pixels connected to the last gate line.
With the rapid advance toward an information-oriented society in recent years, there is an increasing need for flat panel displays having superior characteristics, such as slim profile, lightweight, low power consumption, and the like.
Representative examples of such flat panel displays are liquid crystal display devices (LCD), organic light emitting devices, plasma display devices (PDP), and the like. Among those, the LCDs are frequently employed as monitors for notebook computers or desktop computers owing to their superior resolution, color display capability, and picture quality.
The LCD includes a lower substrate on which thin film transistors (TFTs) functioning as switching elements and pixel electrodes are formed, an upper substrate on which a color filter and a common electrode are formed, and a liquid crystal injected between the lower substrate and the upper substrate and driven by the pixel electrodes and the common electrode to manipulate transmission of light.
The TFTs formed on the lower substrate are connected with gate lines and data lines, and the pixel electrodes are connected with the TFTs. The gate lines are to turn on/off the TFTs for a predetermined time period, and are formed extending in a first direction of the lower substrate, i.e., a horizontal direction. The gate lines are arranged at an equal interval along a second direction of the lower substrate, i.e., a vertical direction. For example, when an LCD has the resolution of 1,024×768, 768 gate lines are arranged in parallel along the second direction of the lower substrate.
The data lines deliver data signals for a time period when the TFTs are turned on, to drive the liquid crystal, thereby charging a storage capacitor. The data lines are formed in the second direction of the lower substrate. The data lines are arranged at an equal interval along the first direction of the lower substrate. For example, when an LCD has the resolution of 1,024×768, 1,024×3 data lines are arranged in parallel.
Thus, pixel regions are defined by Intersecting of the gate lines and the data lines. A TFT and a pixel electrode are disposed on each pixel region.
However, in the case of the related art LCD, to a gate line formed on a last edge of the lower substrate, i.e., 768th gate line, a gate turn-on signal is delivered for a time period 1.5 times longer than that applied to other gate lines so as to indicate that the 768th gate line is the last gate line. Accordingly, since a charge amount charged in a storage capacitor of a pixel connected with the 768th gate line is larger than that charged in a storage capacitor of a pixel connected with other gate line, the brightness of the pixel connected with the 768th gate line is higher than that of the pixel connected with other gate line, so that the brightness uniformity decreases.